* Added information about the verify and expand commands to
  CURLOPT_MAIL_RCPT.
* Reworked CURLOPT_CUSTOMREQUEST section, adding information about IMAP
  and SMTP custom commands.

* Added SMTP section to --request
* Expanded --mail-rcpt to describe the usage when using the verify and
  expand commands.

Although this option should have already been set, the SMTP module can
now download information from and send instructional commands to, an
SMTP server, requiring the option to be set in order to perform a mail
transfer.

Incorrectly processed multiline server greeting responses as "wanted"
continue responses in smtp_endofresp(), from commit f16c0de4,
which in turn broke the SMTP server detection in the test suite,
because the EHLO command would not be sent.

warning: unused variable 'smtpc'

Added a loop to smtp_statemach_act() in which Curl_pp_readresp() is
called until the cache is drained. Without this multiple responses
received in a single packet could result in a hang or delay.

Similar to the processing of untagged CAPABILITY responses in IMAP moved
the processing of multiline EHLO responses to smtp_state_ehlo_resp() and
introduced an internal response code of one to differentiate a multiline
continuation from the end of command. This also allows for the separate
processing of multiline responses from commands such as VRFY and EXPN.

singleipconnect() did not return the open socket descriptor on some
errors, thereby sometimes causing a socket leak. This patch ensures
the socket is always returned.

The ipv6 auto-detect test in configure returns a false negative when
CFLAGS contains -Werror=implicit-function-declaration. (I have been
using this flag to detect code issues that would result in SEGVs on
x86_64-cygwin.)

Patch-by: Yaakov Selkowitz
Bug: http://curl.haxx.se/bug/view.cgi?id=1304

Even though this is only a formality (since not many people build on
Mavericks while targeting Leopard), since we still support Leopard
at the earliest, we might as well be pedantic.

It turns out that some of the constants necessary to make this feature
work are missing from Snow Leopard's Security framework even though
they are defined in the headers.

Bug: http://curl.haxx.se/mail/lib-2013-11/0076.html
Reported by: myriachan

Rather than set the authentication options as part of the login details
specified in the URL, or via the older CURLOPT_USERPWD option, added a
new libcurl option to allow the login options to be set separately.

- better describe what happens when 1 is specified as parameter
- clarify what "is ignored" means for NSS builds

This patch fixes and issue introduced in commit 7d7df831, if the
tunnel state was TUNNEL_CONNECT, waitconnect_getsock() would return a
bitmask indicating a readable socket but never stored the socket in the
return array.